FANUC6FX1136-8BA01Sinumerik 880 / 880M Multiport Memory Board with Real-Time Clock — 128 KB Battery-Backed RAM, NC Ready 2 Contact, Measuring Pulse Inputs

Product Description

What this part is

This is the multiport memory board with clock for the Siemens Sinumerik 880 and 880M CNC control — Siemens designation BGR MULTIPORT, MIT UHR (ZENTRALPUFFERUNG, INTEGR. RAM). It is a Euro-format plug-in card that seats in the Sinumerik 880 rack and connects to the NC rack backplane bus. It does three jobs that a bare description of “circuit board” completely hides: it provides the centrally buffered, battery-backed RAM that retains machine parameters and the system buffer through a power-down, it carries the real-time clock the control uses to keep system time, and it hosts a set of central housekeeping functions for the rack.

Correcting the source data

The brand on this record read FANUC and the previous description claimed it was manufactured by Fanuc in the United States. Neither is correct and we have fixed the brand field. A 6FX prefix is Siemens Sinumerik — it is one of the most recognisable order-code prefixes in machine tool controls, and Fanuc has never used it. Fanuc CNC boards carry A16B, A20B and A02B prefixes. A Sinumerik 880 board searched under Fanuc reaches nobody, which is the practical cost of that error.

The number 570 368 9101.01 also on the board is a Siemens internal drawing or PCB layout number, not an alternative order code. It is worth keeping as a search term because it is what is silkscreened on the board and it is often what a maintenance engineer reads off a card in a rack, but the orderable number is 6FX1136-8BA01.

Decoding the order code

6FX – Siemens numerical control and feed drive product area (Sinumerik)1136 – the Sinumerik 800-series card block. Its sibling 6FX1136-3BA01 is the Servo-CPU board for the same rack, which is a good illustration of how much the last digits change the function.8BA01 – the multiport memory board with clock and central buffering
Also written 6FX11368BA01, 6FX1136 8BA01 and 6FX1136-8BA-01.

Published specifications

Platform: Siemens Sinumerik 880 and 880MModule description: multiport memory board with clock, central buffering, integrated RAMMemory: 128 KB lithium-battery-backed Link RAM, retaining the system buffer and machine parameters through power-downReal-time clock: integrated CMOS RTC — the control’s system time depends on this boardBus functions: bus priority logic control and system clock pulse generationMeasuring inputs: 2 measuring pulse inputs for in-process measurement functionsRelay output: NC Ready 2 contactMonitoring: temperature monitoring circuitForm factor: Euro-format plug-in card, mates to the 880 rack backplane bus

What these specs mean in practice

Because this board holds both the battery-backed parameter RAM and the real-time clock, its failure mode is distinctive and often misdiagnosed. A control that loses machine parameters on every power-down, or that comes back with the wrong date and time, or that reports a parameter checksum fault after a weekend shutdown, is pointing at this board or its backup battery — not at the CPU. Before you replace the board, replace the battery and try again; a flat lithium cell produces exactly the same symptoms and costs a fraction as much.

The NC Ready 2 relay contact matters for your safety and interlock wiring. It is a hardware output the machine builder typically uses in the enable chain, so a failed relay on this card can present as a machine that will not enable at all, with no obvious NC alarm. Trace that contact before condemning a drive.

The two measuring pulse inputs are what the control uses for in-process probing and measurement cycles. If your machine has a touch probe or in-cycle gauging and those functions have stopped working while everything else runs, this card is in the signal path.

Sinumerik 880 predates 840D by a long way, so this is deep legacy territory. Boards are not being made, documentation is scarce, and a working spare on the shelf is the difference between a day of downtime and a month of it.

What is not included

Board only, one card. Not supplied: the lithium backup battery (fit a fresh one — see above, it is the single most likely cause of the symptoms this card gets blamed for), the Sinumerik 880 rack or card cage, the backplane, the Servo-CPU board or any other card in the rack, ribbon or backplane cabling, machine parameters or any stored data, and documentation. This is a rack card and does nothing standalone.

Installation and setup notes

Power the control fully down and observe static precautions before pulling or seating any 880 rack card. Note the slot position before removal; Sinumerik 800-series racks are slot-specific and cards are not freely movable. Because this board carries the battery-backed parameter store, back up your machine parameters before you touch it — on a control of this generation that may mean a tape or serial dump, and it may mean transcribing them by hand, but doing it afterwards is not an option. Expect to re-enter the date and time after fitting. If the machine has probing functions, verify them as part of commissioning rather than assuming.

Interchange guidance

Search forms include 6FX1136-8BA01, 6FX11368BA01, 6FX1136 8BA01 and the board marking 570 368 9101.01. Do not substitute 6FX1136-3BA01 — that is the Servo-CPU board for the same rack, an entirely different card in the same family, not an equivalent. Sinumerik 880 cards are strongly tied to the rack generation and to the machine’s software version; match the full order code. Siemens has long discontinued the Sinumerik 800 series with no factory replacement path; surplus, reman and specialist board repair are the supply channels.